1. Field of the Invention
The present invention relates generally to the field of multiple receiving antennae systems and particularly to a method and apparatus for using automatic gain control (AGC) systems for adjusting the gain of the multiple receiving antennae systems.
2. Description of the Prior Art
As computers have gained enormous popularity in recent decades, so have networking the same allowing for access of files by one computer from another. More recently and with the advent of wireless communication, remote and wireless networking of computers is gaining more and more notoriety among personal users, small and large business owners, factory facilities and the like.
With regard to the wireless networking of personal computers including laptops, a particular modem, namely modems adapted to the IEEE 802.11a or 802.11g industry standard, are commonly employed. However, to improve reception of data at higher rates wireless receivers often employ multiple antennae. In the design of multiple receiving antennae systems new technical features and challenges arise. For example conventional 802.11g compliant receivers decode data modulated in both the time (complementary code keying (CCK)) and frequency domains (orthogonal frequency division multiplexing (OFDM)).
The gain of the multiple antennae needs to be adjusted to enhance reception of the incoming signals. In a conventional multiple receiving antennae system a single automatic gain control (AGC) module is used to generate the same gain for all the antennae therein. However, using the same gain may cause the incoming signals with more signal power to saturate the radio frequency (RF) systems while preventing the incoming signals with lower signal power from fully utilizing the dynamic range of the analog to digital converter (ADC) modules included in the multiple receiving antennae system. This is because the signal powers of the incoming signals for different antennae are in general different. In addition, different RF systems have in general different gain settings. Therefore, applying the same gain to different RF systems may degrade the performance of the multiple receiving antennae system.
In light of the foregoing, it is desirable to develop a method and apparatus for adjusting the gain of multiple receiving antennae systems while fully utilizing the dynamic range of the ADC modules included therein.